A six-axis anthropomorphic arm is an extraordinary machine, but it does not speak the language of 3D-printing software. For a large-format material-deposition project we developed a custom CAM postprocessor that translates tool paths into KRL programs executable by the KUKA controller, synchronising the extruder and managing the robot's limits. The technical account of how we got there.
Project developed for a client in the manufacturing sector · Domain: industrial robotics / additive manufacturing · Confidential details anonymised.
Slicing software for 3D printing generates G-code for 3-axis Cartesian machines: a head that moves in X-Y-Z. A 6-axis robot does not run G-code and reasons in a completely different way — in terms of joints and poses in space.
The robot can reach the same point with infinite joint configurations. You need rules to choose the right one along the whole path, keeping the tool correctly oriented with respect to the surface.
Material deposition must start, stop and modulate its flow rate in sync with the motion: if the robot accelerates and the extruder doesn't (or vice versa), the result is unusable.
Certain poses send the robot into a singularity (loss of controllability) or outside the reachable volume. On a path of thousands of points, these must be anticipated and avoided beforehand, not discovered with the machine at a standstill.
We developed a custom postprocessor that takes the tool path generated by the CAM and turns it into a KRL program ready for the KUKA KRC5 controller. Not a mechanical point-by-point conversion: the postprocessor reasons about the robot's motion.
It manages the tool orientation along the path, keeps the feed rate constant where needed for uniform deposition, synchronises the extruder through the controller's I/O, and applies rules to avoid singularities and out-of-reach configurations. In practice, it translates the language of printing into the language of robotics, protecting the machine from impossible commands.
A postprocessor that generates structured, readable KRL code, parametric on the process data (speed, orientation, flow rate).
Management of the extruder and auxiliaries through the controller's I/O, in phase with the robot's motion.
Checks on singularities, joint limits and work volume applied upstream, over the entire path, before execution.
The robot runs complex deposition paths repeatably, with synchronised extrusion and without stopping on impossible poses. The same arm becomes a reconfigurable machining platform, no longer just a manipulator.
A slicer generates G-code for 3-axis Cartesian machines. A 6-axis robot does not run G-code and has extra degrees of freedom to manage: tool orientation, choice of joint configuration, singularities. You need a postprocessor that translates the path into robot language (KRL) while taking all of this into account.
It is the component that translates the tool path computed by the CAM software into the specific language of the machine that will execute it — in our case KRL for the KUKA controller. This is where speeds, orientations, process I/O and the machine's constraints are handled.
The approach — custom postprocessor, process synchronisation, handling of the robot's constraints — applies to many processes: material deposition, thermal cutting, milling, dispensing. The process changes, the principle doesn't.
Yes: that is our advantage. Beyond programming the robot, we also design the electronics and firmware of the tool (extruder, sensors, actuators) and make them communicate with the controller. A single point of contact for both robot and end-effector.
Custom CAM postprocessors, end-effector integration, robotised cells for non-conventional processes: if you have a robot to turn into a production machine, let's talk. The initial discovery is free.
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